(Reuters) - Donald Trump’s nominee to head the Department of Homeland Security told a U.S. Senate committee on Wednesday there was no need to build a wall on the Mexican border “from sea to shining sea” in remarks that contrasted with the president’s campaign pledge.

Kirstjen Nielsen repeated at her confirmation hearing what her predecessor, John Kelly, had said about the project. Kelly, Nielsen’s former boss, stepped down as head of the department this year to be Trump’s chief of staff.

Building a wall along the U.S.-Mexico border was one of Trump’s central campaign promises but so far only prototypes have been built as funding remains in question.

Nielsen, 45, served as Kelly’s deputy in the White House and before that as his chief of staff when he was secretary of homeland security in the opening months of Trump’s presidency.

In response to questions from senators on the Homeland Security Committee, Nielsen said she would work with “state and local actors on the ground” to find the best solutions for border security, including increasing the use of technology such as unmanned surveillance aircraft.

The ranking Democrat on the committee, Senator Claire McCaskill, raised concerns that no cost-benefit analysis had been done on the need for the wall as compared to other homeland security initiatives facing cuts in the president’s budget.

“These decisions shouldn’t be based on politics,” McCaskill said at the hearing.

Nielsen responded that any decision about resources needed to be “risk based.”

If confirmed by the Senate, Nielsen would take the reins at a department with more than 240,000 employees that is responsible for issues such as U.S. border and airport security, immigration policy, disaster response and refugee admissions.

She is a cyber security expert and highlighted those concerns in her opening remarks. “Cyber criminals and nation states are continually looking for ways to exploit our hyperconnectivity,” Nielsen said.

A day before the hearing a bipartisan group of dozens of former U.S. Homeland Security officials sent letters supporting her nomination.

Nielsen served in the administration of Republican President George W. Bush as Special Assistant to the President for Homeland Security and was involved in revising disaster relief policies after Hurricane Katrina in 2005.

When asked by another Democratic senator whether she believed humans were the primary cause of climate change, which scientists have linked to worsening natural disasters, Nielsen said: “I do absolutely believe that the climate is changing and that there are many contributions”.